The center of U.S. anti-terrorist operations in the Horn of Africa is a desolate, dusty military base in the tiny nation of Djibouti, one of Defense Secretary Donald Rumsfeld's stops on his trip to the region last week.

The structure has been nicknamed the "clam shell" - an open-ended, hanger-like building where Donald Rumsfeld spoke to several hundred of the 900 U.S. troops based in Djibouti.

It is one of his so-called town hall meetings, where Mr. Rumsfeld gives soldiers a pep talk and then takes their questions. One wants to know just how long he and his comrades-in-arms, most clad in battle fatigues and some carrying weapons, can expect to be based in the Horn of Africa.

Mr. Rumsfeld said he cannot predict. But he suspects that even two, three or four years from now, Camp Lemonier will probably still be an active base. "One thing is we need to be where the action is and there is no question but that here, this part of the world is an area where there's action," Mr. Rumsfeld said.

A glance at a map explains why. Djibouti is close to both Yemen and Somalia, two countries where al-Qaida terrorists are known to have taken shelter since fleeing the post-September 11, 2001, U.S. anti-terrorist offensive in Afghanistan.

Djibouti's government has also been exceptionally cooperative in the war on terrorism, a point stressed by Mr. Rumsfeld after meeting with Djibouti's President, Ismail Omar Guelleh.

"It's a country that shares our concerns about fanaticism, terrorism, extremism," said the U.S. official. "It's a country that has clearly lived in a part of the world that is important with respect to the global war on terrorism. And we've found that the cooperative approach that we've found here has been very helpful and beneficial to us and I hope to them."

One of the things that is remarkable about the Rumsfeld visit is that the 11 journalists traveling with him are allowed onto the grounds of Camp Lemonier - the first reporters ever permitted inside. This coastal facility, adjacent to Djibouti's main international airport, is considered so sensitive that U.S. officials were initially reluctant to let them enter.

The reason is that about half of the 900 troops based here are Special Operations forces - the secretive, elite soldiers at the point of the spear in anti-terrorist operations. No officials will discuss their activities beyond saying they could be active in a variety of nearby countries, including Yemen, Somalia, Sudan and Kenya as well as Eritrea and Ethiopia.

But some of the tools of the Special Operations trade are visible inside the dirt berms, barbed wire fences and other fortifications designed to keep prying eyes from witnessing what happens at Camp Lemonier.

These tools include sophisticated MH-53 Pave Low Special Operations helicopters configured for undetected penetration missions and an MC-130 Special Operations Combat Talon airplane, designed for sensitive infiltration flights.

The Central Intelligence Agency is also reportedly active from Camp Lemonier, using unmanned Predator drone aircraft to track and attack al-Qaida terrorists, like the six killed recently in nearby Yemen by a Predator-fired Hellfire missile.

But the drones are not visible when reporters drive across the base. Instead, besides the Special Operations aircraft, all that is visible are hectares of dirt, rock and sand, with scattered guard towers, tents, containers and pallets of supplies.

It is a former French base, which U.S. soldiers say was a virtual wreck when they moved in last June. Buildings had been stripped of even pipes and wiring. Goats roamed the property and birds had taken roost in several structures whose roofs had collapsed.

But military engineers have turned things around, despite the intense heat, drought and insects, building new concrete pads, maintenance facilities and living areas. It has, in the words of one military spokesman, "expanded wildly."

Mr. Rumsfeld visited Djibouti after stopping in two other Horn countries - Eritrea and Ethiopia. In both countries, he received pledges of cooperation in the war on terrorism but reporters want to know if he perhaps secured permission to open any more bases.

The Defense Secretary said his visit was not intended to conduct that sort of business. But later in his trip, Mr. Rumsfeld appears to confirm he has been offered access to more military facilities in the Horn.

"Countries do from time to time suggest that they would like us to use some port or some base or some test range or whatever from time to time. But we don't have any particular plans to announce," the defense secretary said.

In the meantime, a U.S. Navy command-and-control ship has now arrived in the waters off Djibouti to take charge of a new Horn of Africa Joint Task Force. The new headquarters group, led by a Marine Corps General, includes some 400 personnel who are eventually expected to move ashore and set up shop at Camp Lemonier.